1. Field of the Invention
The present invention relates generally to forging presses and methods of controlling the same, and more particularly to a forging press that includes both a flywheel and a servomotor as a drive source to cause an eccentric shaft to rotate and to a method of controlling the same.
2. Description of the Related Art
As a machine press that causes a slide to be moved upward and downward by the rotation of an eccentric shaft, a hybrid press has been proposed that includes both a flywheel and a servomotor as a drive source to cause the eccentric shaft to rotate.
The hybrid press described above includes a flywheel connected to an eccentric shaft via a clutch and a servomotor connected to the eccentric shaft via a clutch and brake unit. The hybrid press is described as being capable of increasing productivity by increasing the lowering speed and the rising speed of a slide by performing pressure forming with the rotational energy of the flywheel and causing the slide to move upward and downward before and after pressure forming with the servomotor.
However, because of the limited capacity of the servomotor, such a hybrid press has been developed only as a small-size hybrid press whose driven system such as a slide is limited in inertial mass, and has not been developed as a large-size hybrid press whose driven system has large inertial mass. Therefore, the conventional hybrid presses are small in size, and there have been no large-size hybrid presses.